A small but growing percentage of teenage American cell phone users have received ads on their cell phones, according to findings of a teen technology study scheduled to be released Wednesday by Ball State University.

The study, based on a survey of 821 junior high and high school students, found that 17 percent have received an ad on their cell phones--a percentage that Ball State's faculty expects to rise as marketers obtain more cell phone numbers.

Study author Michael Hanley, an assistant professor in the journalism department at Ball State, was surprised that the number was so high, "given that the only way legally that that could happen is if they signed up on a site." Hanley said that before this survey, it was difficult to find subjects who had been the targets of mobile advertising. "This should be relatively good news for the advertising industry, as they are obviously sending messages and reaching that market."

The "Teen Technology Survey" was conducted in two phases. The first was a written survey handed out to 180 Chicago-area high school juniors and seniors in October 2004. The second phase was an online survey, which was completed by 641 teens in 20 states during November and December 2004. Preliminary results are expected to be released Wednesday, to be followed in several weeks by a more detailed analysis.

The online participants were recruited by the Ball State American Advertising Federation student chapter members, and their friends and families. Hanley stressed that this survey was composed of a convenience sample, and not a scientifically constructed random sample--and therefore could not be generalized to the general teen population of the United States.

The survey also complemented the trend indicated by a September study by the Pew Internet & American Life Project, which found that instant messaging is gaining popularity among American adults, with similar data regarding American teens. According to Hanley's survey, 84 percent of teens surveyed use instant messaging when online, and 48 percent of teens use their cell phones to send text messages. According to the Pew survey, which sampled 2,204 adults over 18, 42 percent of Internet users--roughly 53 million American adults--reported using instant messaging.

The Ball State survey also found that the teens surveyed used instant messaging more often than any other method to communicate with their friends, coming in at 40 percent--with cell phones and land lines coming in at 24 and 29 percent, respectively. Over a quarter of teens said they had used instant messaging to perform traditionally more personal communications, like asking someone out or breaking off a relationship.

The teens surveyed in the Ball State sampling resided in Alabama, California, Connecticut, Florida, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Massachusetts, Michigan, Minnesota, New Jersey, New York, North Carolina, Ohio, Oregon, Texas, and Washington. The study has a plus or minus 7.3 percent margin of error.